> ## Documentation Index
> Fetch the complete documentation index at: https://docs.roboticks.io/llms.txt
> Use this file to discover all available pages before exploring further.
# IEC 62061
> Machinery functional safety derived from IEC 61508. SIL CL mapping. The IEC route to safety-related machinery control systems, alongside the ISO 13849 PL route.
# IEC 62061
IEC 62061:2021, *Safety of machinery — Functional safety of safety-related control systems*, is the IEC route to demonstrating that a machinery control system reaches the safety integrity its risk assessment requires. It is the sector-specific adaptation of IEC 61508 for machinery, and is harmonised under EU MR 2023/1230 (citation publication in the EU OJ is ongoing).
It coexists with [ISO 13849-1](/standards/iso-13849): both are accepted routes. IEC 62061 uses **SIL CL** (Safety Integrity Level Claim Limit, 1–3) where ISO 13849 uses **PL** (Performance Level, a–e). The two are approximately equivalent for the bands where they overlap; the choice between them is most often driven by component-supplier datasheets (which level the component is rated against) and by your safety engineer's preference.
**Roboticks is audit-readiness tooling, not a certified toolchain.** We assemble the evidence your notified body, certification body, or QA process ingests. We do not replace tool qualification (DO-178C, ISO 26262-8 TCL) and we do not issue conformity assessments. Verify the regulatory interpretations on this page against the standard text and your accredited assessor.
## SIL CL vs SIL
IEC 62061 uses **SIL CL** for sub-system claim limits and reserves **SIL** for the integrated function:
| SIL CL | Bands |
| -------- | --------------------------------- |
| SIL CL 1 | Sub-system PFHd in the SIL 1 band |
| SIL CL 2 | SIL 2 band |
| SIL CL 3 | SIL 3 band |
A safety function composed of subsystems aggregates SIL CLs (per the formulas in IEC 62061 Clause 6.6) to a final SIL.
## SIL CL ↔ PL approximate mapping
| SIL CL (IEC 62061) | PL (ISO 13849) |
| ------------------ | -------------- |
| 1 | b / c |
| 2 | c / d |
| 3 | d / e |
The mapping is approximate; the exact correspondence depends on architecture, MTTFd, DCavg, and CCF. For a given safety function, **either route is acceptable** — but a single function should be assessed through one route or the other, not both.
## What Roboticks supports
* **Clause-level derivation** from IEC 62061.
* **SIL CL annotation** on requirements via the `asil_pl` field (`SIL CL 1`, `SIL CL 2`, `SIL CL 3`).
* **Subsystem-level verification evidence** — JUnit aggregation per subsystem, coverage per module, static-analysis findings per file.
* **Architecture-as-config** — the project's safety architecture (which subsystems implement which safety functions) lives in `roboticks/architecture.yaml`; the evidence pack renders the architecture diagram in the PDF.
## What Roboticks does not do
* We do not compute SIL or SIL CL — these are determined by hazard analysis and architectural calculation Roboticks does not perform.
* We do not validate component supplier SIL CL claims — those rest on supplier-provided certification.
* We do not generate the IEC 62061 functional-safety plan — that is your safety engineer's product (though we can attach it as supplementary evidence).
## Example SIL CL 2 requirement
```yaml theme={null}
- id: REQ-SAF-105
title: Light-curtain interrupt halts cell motion SIL CL 2
type: safety
asil_pl: "SIL CL 2"
derives_from:
- standard: iec-62061-2021
clause: "§6.6 Safety function realisation — subsystem architecture B"
edition: "2021"
- standard: iec-61496-1-2020
clause: "§5.4 Detection capability"
edition: "2020"
text: |
On interruption of the cell light curtain, the cell control system
shall command a Category 1 stop within 200 ms. The function shall
achieve SIL CL 2 via dual-channel light-curtain input and
cross-monitoring of the stop response, with diagnostic coverage
per IEC 62061 §6.7.
acceptance:
- test: tests/cell/test_light_curtain.py::test_interrupt_commands_stop
- test: tests/cell/test_light_curtain.py::test_response_under_200ms
- test: tests/cell/test_light_curtain.py::test_dual_channel_symmetry
- test: tests/cell/test_light_curtain.py::test_diagnostic_on_channel_fault
```
Cross-derives from [IEC 61496](/standards/iec-61496), which defines the light-curtain itself.
## The architecture-as-config pattern
For projects under IEC 62061, declaring the safety architecture in a structured form pays off across the lifecycle. Roboticks accepts an `architecture.yaml`:
```yaml theme={null}
safety_functions:
- id: SF-001
name: Cell light-curtain interrupt → motion stop
sil_cl_required: 2
subsystems:
- id: SS-LC-A
name: Light curtain channel A
type: input
sil_cl_capability: 3
supplier: "Acme Sensing"
pfhd: 5.0e-10
- id: SS-LC-B
name: Light curtain channel B
type: input
sil_cl_capability: 3
supplier: "Acme Sensing"
pfhd: 5.0e-10
- id: SS-LOGIC
name: Safety PLC
type: logic
sil_cl_capability: 3
supplier: "Siemens"
pfhd: 2.0e-9
- id: SS-DRIVE
name: Servo drive STO
type: output
sil_cl_capability: 2
supplier: "ABB"
pfhd: 1.0e-8
realised_by_requirements:
- REQ-SAF-105
```
The platform renders the architecture in the evidence-pack PDF and surfaces it in the dashboard. It does not aggregate PFHd to verify the SIL — that is your safety engineer's calculation — but it makes the architecture visible alongside the verification evidence.
## Suggested test patterns
| SIL CL | Architecture | Pattern |
| ------ | ------------------------- | ------------------------------------------------------------------------------- |
| 1 | Single channel | Nominal-function tests; deadline assertions |
| 2 | Dual-channel | Above + single-channel-fault injection; cross-check tests |
| 3 | Dual-channel with high DC | Above + comprehensive fault-detection coverage; periodic-self-test verification |
## Pinning
```bash theme={null}
rbtk standard pin iec-62061-2021 --project acme-robotics/firmware
```
IEC 62061 is part of the `industrial-robot-eu` and `amr-eu` bulk templates.
## Next steps
The PL-based alternative route.
The parent standard.
The protective-equipment standard cross-cited from IEC 62061.